[pkg/ottl] OTTL Sprintf Function

[sinkingpoint]

Component(s)

pkg/ottl

Is your feature request related to a problem? Please describe.

When using OTTL, it's often useful to be able to construct strings in various ways. We do have a few ways of doing this already (e.g. Concat), but nothing as flexible as a generic Sprintf. For example, we have no way of padding ints (%02d in Sprintf)

Describe the solution you'd like

I would like to introduce a new OTTL function, Sprintf which takes a format string, and an array of fields, and calls fmt.Sprintf with those arguments.

This would require introducing a new Getter which gets a generic interface{}, rather than the existing Getters which return concrete types.

Describe alternatives you've considered

We can sort of get there with creative uses of Concat, but this quickly becomes unruly with complex definitions. e.g. this is one we have:

Concat([attributes["appname"], attributes["hostname"], Concat([Year(Now()), Month(Now()), Day(Now())], "-"), Concat(["service-", Hour(Now()), ".log"], "")], "/")

Which would look like:

Sprintf("%s/%s/%d-%d-%d/service-%d.log", attributes["appname"], attributes["hostname"], Year(Now()), Month(Now()), Day(Now()), Hour(Now()))

Additional context

No response

[github-actions]

Pinging code owners:

• pkg/ottl: @TylerHelmuth @kentquirk @bogdandrutu @evan-bradley

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[evan-bradley]

I think this makes sense. It should be fairly easy to implement, we already have a untyped getter (ottl.Getter).

[github-actions]

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Pinging code owners:

• pkg/ottl: @TylerHelmuth @kentquirk @bogdandrutu @evan-bradley

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